Diaphragm system control having a magnetically retained closure element

ABSTRACT

A diaphragm pump having a conveying chamber and a working chamber, wherein the conveying chamber comprises a pressure connection and a suction connection, and the working chamber can be or is filled with a hydraulic fluid and is operatively connected to a pressure generator in order to apply an oscillating pressure to the hydraulic fluid, further comprising a diaphragm which has at least one diaphragm layer and a diaphragm core and which separates the conveying chamber and the working chamber from one another, and which can be moved from a pressure stroke position into a suction stroke position and back again, the volume of the conveying chamber in the pressure stroke position of the diaphragm being smaller than in the suction stroke position. The diaphragm is or can be brought into operative connection with a diaphragm return device comprising a traction rod, which applies or can apply a force to the diaphragm in the direction of the suction stroke position and further comprising a storage chamber for accommodating the hydraulic fluid, the working chamber and the storage chamber being connected to one another via a channel closed by a closure element.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a National Stage Application under 35 U.S.C. § 371 of PCT/DE2019/100407, filed on May 6, 2019, which claims priority to German Patent Application having serial number 10 2018 111 601.2, filed on May 15, 2018, which is incorporated by reference herein.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to a diaphragm system control having a magnetically retained closure element.

Description of the Related Art

Diaphragm pumps have a delivery chamber, which has a suction connector and a pressure connector, and a working chamber, which is separated from the delivery chamber by a diaphragm. In order to deliver a medium, the diaphragm is moved back and forth in an oscillating manner between a first position and a second position in that the working chamber is filled with a hydraulic fluid which is subjected to an oscillating pressure. Here, the two positions of the diaphragm are normally referred to as the pressure stroke position and as the suction stroke position.

It is normally the case that the pressure connector is connected to the delivery chamber via a pressure valve in the form of a check valve, and that the suction connector is connected to the delivery chamber via a suction valve likewise in the form of a check valve. During the movement of the diaphragm from the first position into the second position, the so-called suction stroke, the volume of the delivery chamber is increased, whereby the pressure in the delivery chamber decreases. As soon as the pressure in the delivery chamber drops below the pressure in a suction line connected to the suction connector, the suction valve is opened and medium to be delivered is sucked into the delivery chamber via the suction connector. As soon as the diaphragm again moves from the second position in the direction of the first position (this being the so-called pressure stroke), the volume in the delivery chamber is decreased and the pressure in the delivery chamber increases. The suction valve is closed off in order to prevent the medium to be delivered from flowing back into the suction line. As soon as the pressure in the delivery chamber exceeds the pressure in a pressure line connected to the pressure connector, the pressure valve is opened, with the result that the delivery medium present in the delivery chamber can be forced into the pressure line.

The diaphragm itself can in this case be resiliently preloaded in the direction of the suction stroke position. Here, the diaphragm at all times assumes a position in which the forces acting on the diaphragm cancel one another out. Here, under normal conditions, the forces generated by the fluid pressure in the delivery chamber and by the resilient preloading in the direction of the suction stroke position act counter to the forces generated by the fluid pressure in the working chamber.

Subjecting the hydraulic fluid to an oscillating pressure consequently results in an oscillatory movement of the diaphragm and, in association with this, in an oscillatory pumping process for the fluid to be delivered from the suction line into the pressure line.

Hydraulically operated diaphragm pumps are preferably used in the delivery of fluids to be delivered at high pressures, since, as a result of the hydraulic fluid, uniform loading of the diaphragm is realized and the latter consequently has a long service life.

The pressurization of the hydraulic fluid by way of the oscillating pressure is normally realized here by means of a moving piston. Here, it may be the case that, in the event of heavy soiling of the suction valve or flow around the piston, the amount of fluid in the working chamber deviates from the desired amount. In this case, it is possible either that too much hydraulic fluid is accumulated in the working chamber, with the result that the diaphragm is deflected beyond its pressure stroke position, or that too little hydraulic fluid is present in the working chamber, with the result that the diaphragm cannot reach the pressure stroke position. In the first case, there is the risk of excessive loading of the diaphragm, which reduces the service life thereof and can lead to damage. In the second case, the delivery volume per stroke is undesirably reduced.

Ideally, the supply of the diaphragm pump is to be ensured under all load and operating conditions, in order to avoid damage to the diaphragm pumps and in particular to the diaphragm itself. Malfunctions which can arise for example due to a closed or soiled suction line are in particular problematic here. In this case, too little or no fluid to be delivered is introduced into the delivery chamber during the suction stroke. In deviation from normal operation, the forces acting from the fluid pressure in the delivery chamber act counter to the forces generated by the fluid pressure in the working chamber and the forces generated by the resilient preloading. As a result of the amount of fluid to be delivered being too small in the delivery chamber, the diaphragm can be deflected beyond the pressure stroke position since the fluid pressure in the delivery chamber is too low.

The prior art describes solutions to said problem, DE 10 2013 105 072 A1 for example disclosing a solution according to which a movement of the diaphragm beyond the pressure stroke position opens up a passage to a storage chamber of the hydraulic fluid, with the result that the pressure in the working chamber is automatically reduced. For this purpose, a closure element is situated on a return element of the diaphragm and is subjected to pressure by means of spring force in order to close off the passage between the working chamber and the storage chamber. If the diaphragm is then moved beyond the pressure stroke position, then the closure element is moved away from the passage, so that said passage is open and equalization of pressure between the working chamber and the storage chamber takes place. This leads to the pressure in the working chamber dropping and the return element moving the diaphragm in the direction of the suction stroke position again.

However, the solution known from DE 10 2013 105 072 A1 has the disadvantage that, owing to component tolerances of the elements used there, the holding force of the closure element can vary. Consequently, a precise holding force of the closure element cannot be set, and in particular cannot be ensured during a relatively long operation. Moreover, the closing function of the closure element described there depends on the structural size of and the distance covered by the diaphragm counter to which the closure element, which is subjected to force by the spring element, acts. It is furthermore disadvantageous that the closure element does not work in a wear-free manner since transverse forces act on the closure element.

SUMMARY OF THE INVENTION

The object of the present invention is therefore to overcome the disadvantages of the prior art, and in particular to provide a diaphragm pump which comprises a precise and wear-free safeguarding apparatus which prevents damage to the diaphragm in the event of a malfunction.

Said object is achieved by a diaphragm pump having a delivery chamber and having a working chamber, wherein the delivery chamber comprises a pressure connector and a suction connector, and wherein the working chamber is able to be or is filled with a hydraulic fluid and is operatively connected to a pressure-generating apparatus in order for the hydraulic fluid to be subjected to an oscillating pressure, furthermore comprising a diaphragm, having at least one diaphragm layer and a diaphragm core, which separates the delivery chamber and the working chamber from one another and which is able to be transferred from a pressure stroke position into a suction stroke position and back again, wherein the volume of the delivery chamber is smaller in the pressure stroke position of the diaphragm than in the suction stroke position thereof, and wherein the diaphragm is able to be brought into or is in operative connection with a diaphragm return device comprising a tension rod, which subjects or is able to subject the diaphragm to a force in the direction of the suction stroke position, and furthermore comprising a storage chamber for accommodating the hydraulic fluid, and wherein the working chamber and the storage chamber are connected to one another via a channel closed off by a closure element, wherein the closure element is connected, in a manner movable relative to the tension rod, to the latter such that the closure element can be transferred from a closure position into an opening position and back, and wherein the closure element comprises a magnet, and/or is operatively connected to a magnet, which locks the closure element in the closure position, and wherein the closure element is transferred into the opening position and the channel is open if the diaphragm is deflected beyond the pressure stroke position from the suction stroke position.

As described, in the normal situation, the forces generated by the fluid pressure in the delivery chamber and by the resilient preloading in the direction of the suction stroke position act counter to the forces generated by the fluid pressure in the working chamber. If too much working fluid is present in the working chamber, the diaphragm can in this case be deflected beyond the pressure stroke position since the fluid pressure in the working chamber is too high.

The invention is based here on the surprising finding that a movement of the diaphragm beyond the pressure stroke position can be prevented in an effective manner if said movement of the diaphragm is coupled to an opening process for the channel according to the invention. In this case, if the diaphragm is moved beyond the pressure stroke position, then the closure element opens up the channel and the fluid pressure in the working chamber drops. Here, the maximum permitted deflection of the diaphragm beyond the pressure stroke position can be defined by the selection of the magnetic force of the magnet comprised by the closure element or operatively connected thereto.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a detail of a first embodiment of a diaphragm pump according to the invention in a lateral sectional view;

FIG. 2 shows a detail of a second embodiment of a diaphragm pump according to the invention in a lateral sectional view;

FIG. 3 shows a detail of a third embodiment of a diaphragm pump according to the invention in a lateral sectional view; and

FIG. 4 shows a detail of a fourth embodiment of a diaphragm pump according to the invention in a lateral sectional view.

DETAILED DESCRIPTION

A diaphragm pump and system control having a magnetically retained closure element are provided. The closure element can move relative to a diaphragm return device and is connected thereto. This relative movement ensures that the channel remains closed as long as the diaphragm moves within the predefined deflections. The magnet(s) ensures/ensure the closed state of the channel.

Several embodiments for bringing the magnet(s) into operative connection with the closure element are basically conceivable. According to the invention, it may, according to a first embodiment of the present invention, be preferable here for the working chamber to be arranged in a housing, wherein the housing, in the region of the channel, in particular around the channel, comprises a magnet or forms a first magnet, wherein the magnet is operatively connected to the closure element at least in the closure position of the latter.

According to one embodiment, it has proven to be advantageous if the housing through which the channel runs is itself magnetic and/or comprises a magnet. In this way, the closure element, which is movably connected to the return device, is locked in its position without itself needing to comprise a magnet. Rather, it is operatively connected to the magnetic field of the magnet integrated into the housing.

Alternatively or additionally, according to a second embodiment of the present invention, it may be advantageous for the closure element to comprise a second magnet, in particular in the region of its end facing the channel, in particular on the end facing the channel, wherein the magnet is operatively connected to the housing surrounding the working chamber, in particular around the channel, at least in the closure position.

According to said second embodiment, a second magnet is comprised by the diaphragm pump according to the invention as an alternative to the first magnet. The second magnet, arranged on the closure element, is in this case preferably arranged on that end of the closure element facing the channel, so that its magnetic field can interact with the housing of the working chamber, preferably in the region of the channel, and not primarily with the return device as such.

Furthermore, according to a third embodiment of the present invention, a combination of two magnets may also be advantageous, wherein, according to said third embodiment, the closure element comprises a third magnet, in particular on the and/or in the region of its end facing the channel, and the housing surrounding the working chamber, in the region of the channel, in particular around the channel, comprises a fourth magnet or forms a fourth magnet, wherein the polarities of the poles of the mutually opposite regions of the third and fourth magnets are different, and the third and fourth magnets are operatively connected to one another at least in the closure position.

The use of two magnets interacting with one another may prove to be advantageous in particular for the purpose of providing large forces.

According to a further, fourth embodiment, it may be provided that the tension rod comprises a fifth magnet, arranged in particular on and/or in the region of that end of the closure element facing away from the channel, and/or the closure element comprises a sixth magnet, arranged in particular on that end of the closure element facing away from the channel, wherein the polarities of the poles of the mutually opposite regions of the fifth and sixth magnets are identical, and the fifth and sixth magnets are operatively connected to one another at least in the closure position of the closure element.

According to the invention, it has also proven to be advantageous that, instead of by an adhesive force, the closure of the channel by means of the closure element is provided by a pressure force which acts on the closure element in the closure direction and which is generated by the repulsion of two fifth and sixth magnets.

It may prove to be particularly advantageous here for the diaphragm to be releasably fixed by means of a diaphragm-holding element which is introduced at least sectionally into the tension rod, wherein the fifth magnet is comprised by the diaphragm-holding element, in particular on or in the region of that end of the diaphragm-holding element facing away from the diaphragm and inserted into the tension rod.

According to the invention, the diaphragm may be connected to the tension rod by means of a diaphragm-holding element. Here, a diaphragm-holding element normally comprises a rod-like element which is able to be passed through a central opening of the diaphragm layers and which comprises in particular a screw thread and which can be connected to a corresponding thread of the tension rod. If the fifth magnet is then integrated into the rod-like element, said magnet can then be easily accessed, since, for changing the diaphragm, the diaphragm-holding element can be removed. Easy access to the sixth magnet is also made possible.

Furthermore, according to a fifth embodiment of the present invention, it may be advantageous for a seventh magnet, which is operatively connected to the closure element and the housing surrounding the working chamber, to be comprised, wherein the seventh magnet is not fixedly connected to the closure element, the tension rod and the housing, and wherein the magnetic field strength and thus the adhesion of the magnet is at all times greater at the closure element than at the housing.

What is essential to the invention here is that the closure element reliably closes off the channel by means of the generated magnetic force of the magnet(s) as long as the diaphragm is not moved beyond the pressure stroke position.

According to embodiments of the present invention, the magnet(s) may be connected to the tension rod, the closure element and/or the housing or integrated into these. However, the present invention also advantageously provides that the magnet is not connected to said elements and also is not integrated into these, but rather is only operatively connected to one or more of said elements.

With regard to all the embodiments of the invention, it may be advantageous for the first, second, third, fourth, fifth, sixth and/or seventh magnet(s) to be in the form of a spherical magnet, bar magnet, conical magnet, disk magnet or ring magnet.

Depending on the selection of the configuration of magnet, the magnet itself may form the closure element.

It may advantageously be provided here that the magnetic field strength of the first, second, third, fourth, fifth, sixth and/or seventh magnet(s) is selected in such a way that, if, for the pressure difference between the pressure in the storage chamber p₂ and the pressure in the working chamber p₁, it holds that p₂−p₁>a, where a is a predetermined pressure, the closure element is transferred from the closure position into the opening position.

This measure ensures that, in the case of fluid loss in the working chamber, fluid from the storage chamber can be used for replenishment as soon as the pressure in the working chamber drops below a predetermined value.

Furthermore, according to one embodiment of the present invention, it may be preferable that the housing surrounding the working chamber has a wall element comprising the channel, wherein the wall element is movable within the housing relative thereto along the movement direction of the diaphragm return device, and wherein the wall element is preloaded in the direction of the diaphragm return device by means of a spring element.

As a result of the movable arrangement of the wall element of the housing and thus of the channel, it is possible for the additional provision of an overpressure valve to be avoided.

If the pressure in the working chamber increases too sharply, this will lead to a movement of the wall element and thus of the channel at the opening, which has the result that the closure element is moved from the closure position and the channel is thus opened. Consequently, the pressure in the working chamber is reduced again by the connection to the storage chamber.

Here, it may be provided in particular that the resilient preloading of the wall element is selected in such a way that, if, for the pressure difference between the pressure in the storage chamber p₂ and the pressure in the working chamber p₁, it holds that p₁−p₂>b, where b is a predetermined pressure, the wall element moves away from the closure element and, as a result, the channel is opened up.

Finally, it may be provided that the diaphragm return device comprises a further spring element, which is connected to the tension rod, or is operatively connected thereto, such that the diaphragm is preloaded by a force in the direction of the suction stroke position by means of the spring element.

Further features and advantages of the invention emerge from the following description, in which exemplary embodiments of the invention will be discussed by way of example on the basis of schematic drawings, without restricting the invention as a result.

FIG. 1 shows by way of example an embodiment of a diaphragm pump 1 according to the invention with a delivery chamber 3 and with a working chamber 5, which are separated from one another by a diaphragm 7. The working chamber 5 is filled with a hydraulic fluid, and is operatively connected to a pressure-generating apparatus (not shown) in order for the hydraulic fluid to be subjected to an oscillating pressure.

The oscillating pressure in the working chamber 5 of the diaphragm pump 1 allows the diaphragm 7 to be transferable from a pressure stroke position into a suction stroke position and back again, wherein the volume of the delivery chamber 3 is smaller in the pressure stroke position of the diaphragm 7 than in the suction stroke position thereof.

Here, the diaphragm 7 is operatively connected to a diaphragm return device 9 comprising a tension rod 11, which subjects the diaphragm 7 to a force in the direction of the suction stroke position. For this purpose, the diaphragm return device, according to the embodiment shown, comprises a spring 13.

Furthermore, the diaphragm pump according to the invention comprises a storage chamber 15 for accommodating the hydraulic fluid, wherein the working chamber 5 and the storage chamber 15 are connected to one another via a channel 19 closed off by a closure element 17. Consequently, if the closure element 17 is transferred into its opening position, the storage chamber 15 is directly connected to the working chamber 5 via the channel 19.

The closure element 17 is connected, in a manner movable relative to the tension rod 11, to the latter such that the closure element 17 can be transferred from a closure position into an opening position and back. The movable connection of the closure element 17 and the tension rod 11 has a further advantage here. The tension rod 11 itself has to be arranged movably within the working chamber 5 of the diaphragm pump 1, since this has to also perform the movements of the diaphragm 7 from the suction stroke position into the pressure stroke position and vice versa. In order that the closure element 17 remains in the closure position if the tension rod 11 moves within a predefined extent, this in turn is connected movably to the tension rod 11.

Here, FIG. 1 shows that the closure element 17 comprises a magnet 21, which locks the closure element 17 in the closure position, and the closure element 17 is transferred into the opening position and the channel 19 is open if the diaphragm 7 is deflected beyond the pressure stroke position from the suction stroke position. Here, the magnet 21 is comprised directly by the closure element 17 and forms the closing end of the closure element 17.

Here, the magnetic field strength of the magnet 21 is preferably selected in such a way that, if, for the pressure difference between the pressure in the storage chamber 15 p₂ and the pressure in the working chamber 5 p₁, it holds that p₂−p₁>a, where a is a predetermined pressure, the closure element 17 is transferred from the closure position into the opening position.

It can also be seen in FIG. 1 that the housing 23, which surrounds the working chamber 5, has a wall element 25 comprising the channel 19, wherein the wall element 25 is movable within the housing 23 relative thereto along the movement direction of the diaphragm return device 9, and wherein the wall element 25 is preloaded in the direction of the diaphragm return device 9 by means of a spring element (not shown).

The channel 19 can consequently also be opened if the wall element 25 moves away from the closure element 17, with the result that an additional overpressure valve can be dispensed with.

The further figures show further embodiments of the diaphragm pump 1 according to the invention.

In FIG. 2, the diaphragm pump 1 according to the invention comprises a magnet 21′ which is formed by the wall element 25 or is comprised by it. It is self-evident here that the magnet 21′ also is able to be brought into or is in operative connection with the closure element 17.

FIGS. 3 and 4 show two further embodiments of the present invention. Here, in these two embodiments, the magnets 21″ are arranged on that end of the closure element 17 facing away from the channel 19.

As can be seen in FIG. 3, the tension rod 11 comprises a magnet 21″ which is positioned on that end of the closure element 17 facing away from the channel 19, and the closure element 17 comprises a further magnet 21″, wherein the polarities of the poles of the mutually opposite regions of the magnets 21″ are identical and mutual repulsion is realized. Consequently, by contrast to the embodiments according to the invention in FIGS. 1 and 2, magnetic adhesion is not provided, but rather the magnetic fields force the closure element 17 onto the channel 19.

A refinement of the embodiment as per FIG. 3 is shown in FIG. 4. Here, it is shown that the diaphragm 7 is releasably fixed by means of a diaphragm-holding element 27 which is introduced sectionally into the tension rod. The magnet arranged in the tension rod 11 is consequently connected directly to the diaphragm-holding element 27, with the result that the effect of the repelling forces 21″ is identical to that in the exemplary embodiment as per FIG. 3, there being provided however easier access for exchange of the magnets. In this case, an exchange of the magnets 21″ would preferably be realized via partial dismounting of tension rod 11.

The features of the invention that are disclosed in the above description, in the claims and in the drawings may be essential both individually and in any desired combination for the realization of the invention in its various embodiments. 

1. A diaphragm pump, comprising: a delivery chamber and a working chamber, wherein the delivery chamber comprises a pressure connector and a suction connector, and wherein the working chamber is able to be filled with a hydraulic fluid and is operatively connected to a pressure-generating apparatus in order for the hydraulic fluid to be subjected to an oscillating pressure, a diaphragm having at least one diaphragm layer and a diaphragm core, which separates the delivery chamber and the working chamber from one another and which is able to be transferred from a pressure stroke position into a suction stroke position and back again, wherein the volume of the delivery chamber is smaller in the pressure stroke position of the diaphragm than in the suction stroke position thereof, and wherein the diaphragm is able to be brought into operative connection with a diaphragm return device comprising a tension rod, which is able to subject the diaphragm to a force in the direction of the suction stroke position, and a storage chamber for accommodating the hydraulic fluid, wherein the working chamber and the storage chamber are connected to one another via a channel closed off by a closure element, wherein the closure element is connected, in a manner movable relative to the tension rod, to the latter such that the closure element can be transferred from a closure position into an opening position and back, and wherein the closure element comprises a magnet, which locks the closure element in the closure position, and wherein the closure element is transferred into the opening position and the channel is open if the diaphragm is deflected beyond the pressure stroke position from the suction stroke position.
 2. The diaphragm pump of claim 1, wherein the working chamber is arranged in a housing, wherein the housing comprises a magnet that is operatively connected to the closure element at least in the closure position of the latter.
 3. The diaphragm pump of claim 1, wherein the closure element comprises a second magnet, in particular in the region of its end facing the channel, in particular on the end facing the channel, wherein the magnet is operatively connected to the housing surrounding the working chamber, in particular around the channel, at least in the closure position.
 4. The diaphragm pump of claim 1, wherein the closure element comprises a third magnet disposed proximate its end facing the channel, and the housing surrounding the working chamber comprises a fourth magnet, wherein the polarities of the poles of the mutually opposite regions of the third and fourth magnets are different, and the third and fourth magnets are operatively connected to one another at least in the closure position.
 5. The diaphragm pump of claim 1, wherein that the tension rod comprises a fifth magnet arranged proximate the end of the closure element facing away from the channel, and the closure element comprises a sixth magnet, arranged in particular on that end of the closure element facing away from the channel, wherein the polarities of the poles of the mutually opposite regions of the fifth and sixth magnets are identical, and the fifth and sixth magnets are operatively connected to one another at least in the closure position of the closure element.
 6. The diaphragm pump of claim 5, wherein the diaphragm is releasably fixed a diaphragm-holding element which is introduced at least sectionally into the tension rod, wherein the fifth magnet is the diaphragm-holding element.
 7. The diaphragm pump of claim 1 further comprising a seventh magnet operatively connected to the closure element and the housing surrounding the working chamber, wherein the seventh magnet is not fixedly connected to the closure element, the tension rod and the housing, and wherein the magnetic field strength is at all times greater at the closure element than at the housing.
 8. The diaphragm pump of claim 7, wherein any one or more of the first, second, third, fourth, fifth, sixth and seventh magnets are in the form of a spherical magnet, bar magnet, conical magnet, disk magnet or ring magnet.
 9. The diaphragm pump of claim 8, wherein the magnetic field strength of any one or more of the first, second, third, fourth, fifth, sixth and seventh magnets are selected in such a way that, if, for the pressure difference between the pressure in the storage chamber p₂ and the pressure in the working chamber p₁, it holds that p₂−p₁>a, where a is a predetermined pressure, the closure element is transferred from the closure position into the opening position.
 10. The diaphragm pump of claim 1, wherein the housing surrounding the working chamber has a wall element comprising the channel, wherein the wall element is movable within the housing relative thereto along the movement direction of the diaphragm return device, and wherein the wall element is preloaded in the direction of the diaphragm return device by means of a spring element.
 11. The diaphragm pump of claim 10, wherein the resilient preloading of the wall element is selected in such a way that, if, for the pressure difference between the pressure in the storage chamber p₂ and the pressure in the working chamber p₁, it holds that p₁−p₂>b, where b is a predetermined pressure, the wall element moves away from the closure element and, as a result, the channel is opened up.
 12. The diaphragm pump of claim 1, wherein the diaphragm return device comprises a spring element connected to the tension rod, such that the diaphragm is preloaded by a force in the direction of the suction stroke position by means of the spring element. 